PHYS250H: Power Supply Project I


20141011_200321.jpgFor Fall 2014, I decided to continue my work under Professor James Battat with the dark matter detector and he suggested doing so under PHYS250H -- an independent study in the Physics Department -- in order to receive credit for it. However, the project portion of the course veered from work with the PCB I created earlier and towards design of a PCB power supply for his Spring class PHYS310 "Experimental Physics." The power supply was needed for an Electronics student lab, where a five-pin DIN draws in four voltage levels of +12V, -12V, +5V and GND for a solderless breadboard. The PCB I designed would use this connector to draw in the four voltage levels, filter for overcurrent and allow direct input into the rails of a solderless breadboard.
20141011_200709.jpg

At the beginning of the process, Battat and I create a concept diagram demonstrating the overall flow of the power supply and, from it, a rough circuit diagram was generated. Over time, the schematic changed with additional and substitute components. A combination of resistors and capacitors create a low-pass filter and ensures that spikes in the voltage levels will not damage the circuit. Additionally, a zener diode is placed on each voltage line for fast-response protection against unexpected rises in voltage levels. A “positive temperature coefficient” (PTC) resistor will increase its resistance upon overloading or shorting of the load and will maintain high resistance until the overcurrent has been eliminated. The light emitting diodes (or LEDs) on each light serve as indication of successful and safe transmission between the connector and the jumper pins, which will allow for direct integration with the breadboard and other electronics. As a master on-off switch, a set of three jumpers can be used to connect and disconnect the power supply.

With these apsects in mind, I was able to use gEDA (again) to create a small PCB design that incorporated standard footprints and custom-made footprints (like the five-pin DIN connector). We had plans to send the PCB to OSH park -- which has incredible pricing for PCB fabrication.

Comments

Post a Comment

Popular posts from this blog

Hackathon: TechTogether Boston

Image
iOS app Last weekend, I had the wonderful opportunity to participate in Boston's largest all-female and non-binary hackathon! A group of friends and I wanted to digest as much tech and nerd information as possible, and we basically made it our mission to go to nearly every workshop session offered for two days straight. I don't know how we managed this but we did. From 5p on Friday and all day on Saturday, it seemed I bounced from one room to the next with a nap here and there. There was a workshop on rapid prototyping with AdobeXD -- which I am in love with. Then, I was able to create my first phone application during a workshop on iOS app development with Swift  (it's much easier than I had imagined), followed by a workshop at 2am on Android app developmen t. For my very first hackathon-conference, I wanted to focus on skill development and learning, rather than the competition. However, seeing everyone so wrapped up in their individual designs and programming ...
Read more

Women of Color in Graduate School

Image
Recently, I've been asked (by a few people) how it feels to go through graduate school as a woman of color. And, to be completely honest, it's incredibly exciting and exhausting all at the same time. Being a woman of color -- specifically a black woman, particularly in STEM -- has a lot of challenges. If you simply search the phrase "black in graduate school," you will get statistics that are very humbling; articles and think-pieces on how different the Black or person-of-color experience is from students who are not minorities; and other outlets detailing how little support many Black and non-Black students of color feel that they have. In fact, the Council on Graduate Schools recently reported that, in 2017, Black students made up just 11.9% of all first-time graduate students in the United States. (That said, 68% of them were women! So, we are making p r o g r e s s.) I'm not sure what the numbers are at Boston University, but it doesn't seem that far o...
Read more

Truss Design (Final)

Image
We finally made it to the end! After the preliminary design report, it was time to finalize our actual design (since we were given enough materials to make one truss to test). After doing a few more draft sketches and analysis, I was able to pick up on patterns on which types of designs produced the maximum strength (all within the parameters we were given). Finally, I came up with the sketch at the bottom-right, and the MATLAB analysis produced the highest load we were able to reach. We theorized that: two members would buckle first instead of just one (Members 3 and 4); the maximum load is 11.62 ± 0.063N; and the total cost of the truss is $290 (under the budget limit). From there, we moved to prototyping: we cut the straws as close as possible to the lengths specified in our final design. To create uniform gusset plates, our "joints," we used the circular cap of an individual Tropicana Orange Juice bottle. It met the area requirements and acted as a stamp...
Read more